Integrated semiconductor circuits have become the primary components of most electronics systems. These miniature electronic devices may contain thousands of the transistors and other circuits that make up the memory and logic subsystems of microcomputer central processing units and other integrated circuits. The low cost, high reliability and speed of these circuits have led them to become a ubiquitous feature of modem digital electronics.
The fabrication of integrated semiconductor circuits typically takes place in a reactive ion etching system, such as a parallel plate reactor or inductively coupled plasma reactor. A reactive ion etching system may consist of an etching chamber with an upper electrode or anode and a lower electrode or cathode positioned therein. The cathode is negatively biased with respect to the anode and the container walls. The wafer to be etched is covered by a suitable mask and placed directly on the cathode. A chemically reactive gas such as CF4, CHF3, CClF3, HBr, Cl2 and SF6 or mixtures thereof with O2, N2, He or Ar is introduced into the etching chamber and maintained at a pressure which is typically in the millitorr range. The upper electrode is provided with gas hole(s) which permit the gas to be uniformly dispersed through the electrode into the chamber. The electric field established between the anode and the cathode will dissociate the reactive gas forming plasma. The surface of the wafer is etched by chemical interaction with the active ions and by momentum transfer of the ions striking the surface of the wafer. The electric field created by the electrodes will attract the ions to the cathode, causing the ions to strike the surface in a predominantly vertical direction so that the process produces well-defined vertically etched side walls.
Plasmas used for reactive ion etching are highly corrosive species and chamber component surfaces that are exposed to plasmas can degrade quickly. Such degradation of chamber components is costly and can lead to contamination of chamber components or to contamination of a substrate being processed in the chamber. Such degradation requires replacement of contaminated chamber components and/or cleaning of the contaminated chamber components. Such replacement and/or cleaning of the chamber components leads to down-time of the processing chamber.
A substrate support comprising an electrostatic chuck (ESC) for electrostatically clamping a substrate to the support is one such chamber component that may undergo degradation due to exposure to a plasma environment. These types of substrate supports typically comprise a number of components adhered to one another. For example, the support may comprise a cooling plate, a heater element and/or a ceramic plate bonded to one another by a suitable adhesive. To minimize degradation from exposure to the plasma environment, it is common to place an elastomer band around these components in order to protect the adhesive from direct exposure to the plasma environment, such as described in commonly-owned U.S. Pat. No. 7,431,788. However, the elastomer band is then directly exposed to the plasma environment and suffers degradation therefrom. The elastomer band also suffers degradation from compression forces under operational conditions.
The manner in which an elastomer band is disposed around a substrate support may also yield localized stresses in the elastomer band, which leads to the elastomer band being further susceptible to degradation from exposure to the plasma environment. Typically, an elastomer band is disposed around a substrate support by hand in a 5-point star-shaped pattern. Such a disposal pattern creates highly localized stress areas in the elastomer, which are weaker areas in the elastomer and subjects these areas to greater mass loss when exposed to a plasma environment, usually leading to cracking of the elastomer.
Thus, there is a need for an improved method of installing an elastomer band around a substrate support such that the elastomer band demonstrates increased resistance to degradation from exposure to a plasma environment.